Premature infants hospitalized in newborn intensive care units generally require assisted ventilation. The standard method of ventilatory support for these infants is the use of a procedure called intermittent mandatory ventilation (IMV). IMV often results in asynchrony between an infant's spontaneous efforts to breathe and the mechanical breaths delivered by the ventilator. This asynchrony occasionally leads to damage to the lungs and inefficient exchange of oxygen that can affect brain function. More recently, a new type of ventilation device, which is patient-triggered, flow-synchronized ventilation (FSV), has been introduced. No large series has yet been accumulated to determine if FSV is a safer form of therapy in very small premature neonates (those less than 1,000 g in weight). This protocol randomizes premature infants less than 29 weeks of gestational age, who are admitted to the Newborn Intensive Care Unit, to receive either conventional IMV or pressure-limited FSV.